A large study of American patients found that those who drank coffee were less likely to come down with primary sclerosing cholangitis (PSC), an inflammatory disease of the bile ducts causing inflammation and subsequent fibrosis that may lead to cirrhosis of the liver, liver failure, and biliary cancer.

"While rare, PSC has extremely detrimental effects," Dr. Craig Lammert, a Mayo Clinic gastroenterologist, told media. "We're always looking for ways to mitigate risk, and our first-time finding points to a novel environmental factor that also might help us to determine the cause of this and other devastating autoimmune diseases."

Lammert and and his colleagues compared patients with PSC and PBC against a group of healthy study subjects, finding a link between coffee consumption and lowered risk for PSC, but not PBC. The investigators said the healthy patients were much more likely to drink coffee than those with PSC, spending "nearly 20 percent less of their time regularly drinking coffee than the control."

Dr. Konstantinos Lazaridis, a Mayo Clinic liver specialist, said the study suggests a greater difference between the two diseases than previously thought. "Moving forward, we can look at what this finding might tell us about the causes of these diseases and how to better treat them."

Although the cause of PSC is unknown, researchers suspect bacteria, viruses, problems with the immune system, and genetics. The average patient is 40 years old at the time of diagnosis, with the disease more common in men than women, according to the U.S. National Institutes of Health.

The study was funded in part by NIH and the American Liver Foundation.

There have been several studies done in recent years on the health benefits of regular coffee consumption.

In a study published in Alcohol and Alcoholism in March, researchers in Finland found coffee may protect against liver damage in men who drink too much. The researchers collected data on coffee and alcohol consumption from 8,807 men and 10,092 women between the ages of 25 and 74. They also measured blood levels of an enzyme called gamma-glutamyltransferase (GGT), high levels of which are linked to alcoholic liver disease.

They found that in men, high levels of GGT brought on by heavy drinking were significantly reduced by the consumption of more than four cups of coffee per day. There was a similar, though not statistically significant, trend in women. "Coffee modulates the effect of ethanol on serum GGT activities in a dose- and gender-dependent manner," the researchers wrote in their study. "These observations should be implicated in studies on the possible hepatoprotective effects of coffee in alcohol consumers."